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package org.bouncycastle.openpgp;
import java.io.EOFException;
import java.io.InputStream;
import org.bouncycastle.bcpg.BCPGInputStream;
import org.bouncycastle.bcpg.InputStreamPacket;
import org.bouncycastle.bcpg.PublicKeyEncSessionPacket;
import org.bouncycastle.bcpg.SymmetricEncIntegrityPacket;
import org.bouncycastle.bcpg.SymmetricKeyAlgorithmTags;
import org.bouncycastle.openpgp.operator.PGPDataDecryptor;
import org.bouncycastle.openpgp.operator.PublicKeyDataDecryptorFactory;
import org.bouncycastle.util.io.TeeInputStream;
/**
* A public key encrypted data object.
*/
public class PGPPublicKeyEncryptedData
extends PGPEncryptedData
{
PublicKeyEncSessionPacket keyData;
PGPPublicKeyEncryptedData(
PublicKeyEncSessionPacket keyData,
InputStreamPacket encData)
{
super(encData);
this.keyData = keyData;
}
private boolean confirmCheckSum(
byte[] sessionInfo)
{
int check = 0;
for (int i = 1; i != sessionInfo.length - 2; i++)
{
check += sessionInfo[i] & 0xff;
}
return (sessionInfo[sessionInfo.length - 2] == (byte)(check >> 8))
&& (sessionInfo[sessionInfo.length - 1] == (byte)(check));
}
/**
* Return the keyID for the key used to encrypt the data.
*
* @return long
*/
public long getKeyID()
{
return keyData.getKeyID();
}
/**
* Return the symmetric key algorithm required to decrypt the data protected by this object.
*
* @param dataDecryptorFactory decryptor factory to use to recover the session data.
* @return the identifier of the {@link SymmetricKeyAlgorithmTags encryption algorithm} used to
* encrypt this object.
* @throws PGPException if the session data cannot be recovered.
*/
public int getSymmetricAlgorithm(
PublicKeyDataDecryptorFactory dataDecryptorFactory)
throws PGPException
{
byte[] plain = dataDecryptorFactory.recoverSessionData(keyData.getAlgorithm(), keyData.getEncSessionKey());
return plain[0];
}
/**
* Open an input stream which will provide the decrypted data protected by this object.
*
* @param dataDecryptorFactory decryptor factory to use to recover the session data and provide the stream.
* @return the resulting input stream
* @throws PGPException if the session data cannot be recovered or the stream cannot be created.
*/
public InputStream getDataStream(
PublicKeyDataDecryptorFactory dataDecryptorFactory)
throws PGPException
{
byte[] sessionData = dataDecryptorFactory.recoverSessionData(keyData.getAlgorithm(), keyData.getEncSessionKey());
if (!confirmCheckSum(sessionData))
{
throw new PGPKeyValidationException("key checksum failed");
}
if (sessionData[0] != SymmetricKeyAlgorithmTags.NULL)
{
try
{
boolean withIntegrityPacket = encData instanceof SymmetricEncIntegrityPacket;
byte[] sessionKey = new byte[sessionData.length - 3];
System.arraycopy(sessionData, 1, sessionKey, 0, sessionKey.length);
PGPDataDecryptor dataDecryptor = dataDecryptorFactory.createDataDecryptor(withIntegrityPacket, sessionData[0] & 0xff, sessionKey);
encStream = new BCPGInputStream(dataDecryptor.getInputStream(encData.getInputStream()));
if (withIntegrityPacket)
{
truncStream = new TruncatedStream(encStream);
integrityCalculator = dataDecryptor.getIntegrityCalculator();
encStream = new TeeInputStream(truncStream, integrityCalculator.getOutputStream());
}
byte[] iv = new byte[dataDecryptor.getBlockSize()];
for (int i = 0; i != iv.length; i++)
{
int ch = encStream.read();
if (ch < 0)
{
throw new EOFException("unexpected end of stream.");
}
iv[i] = (byte)ch;
}
int v1 = encStream.read();
int v2 = encStream.read();
if (v1 < 0 || v2 < 0)
{
throw new EOFException("unexpected end of stream.");
}
//
// some versions of PGP appear to produce 0 for the extra
// bytes rather than repeating the two previous bytes
//
/*
* Commented out in the light of the oracle attack.
if (iv[iv.length - 2] != (byte)v1 && v1 != 0)
{
throw new PGPDataValidationException("data check failed.");
}
if (iv[iv.length - 1] != (byte)v2 && v2 != 0)
{
throw new PGPDataValidationException("data check failed.");
}
*/
return encStream;
}
catch (PGPException e)
{
throw e;
}
catch (Exception e)
{
throw new PGPException("Exception starting decryption", e);
}
}
else
{
return encData.getInputStream();
}
}
}
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